Protein kinase D2 and heat shock protein 90 beta are required for BCL6-associated zinc finger protein mRNA stabilization induced by vascular endothelial growth factor-A

• Published in: Angiogenesis (London) 2013-07, Vol.16 (3), p.675-688
• Main Authors: Miwa, Daisuke, Sakaue, Tomohisa, Inoue, Hirofumi, Takemori, Nobuaki, Kurokawa, Maki, Fukuda, Shinji, Omi, Kazuya, Goishi, Katsutoshi, Higashiyama, Shigeki
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Biomedicine; Blotting, Western; Cancer Research; Cardiology; Cell Biology; Electrophoresis, Gel, Two-Dimensional; Gene Expression Regulation - physiology; HSP90 Heat-Shock Proteins - metabolism; Human Umbilical Vein Endothelial Cells; Humans; Immunoglobulin J Recombination Signal Sequence-Binding Protein - metabolism; Luciferases; Oncology; Ophthalmology; Original Paper; Protein Kinase C - metabolism; Protein Kinases - metabolism; Real-Time Polymerase Chain Reaction; Receptors, Notch - metabolism; Repressor Proteins - metabolism; Repressor Proteins - physiology; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; RNA Stability - drug effects; RNA Stability - physiology; Signal Transduction - drug effects; Vascular Endothelial Growth Factor A - pharmacology
• ISSN: 0969-6970; 1573-7209
• DOI: 10.1007/s10456-013-9345-x

Vascular endothelial growth factor (VEGF) is a major angiogenic factor that activates pro-angiogenic molecules to generate new vessels. Recently, we identified a VEGF-A-induced pro-angiogenic gene, BCL - 6 associated zinc finger protein ( BAZF ), in endothelial cells. BAZF interacts with CBF1, a transcriptional regulator of Notch signaling, and downregulates Notch signaling by inducing the degradation of CBF1. A signal inhibition assay with a combination of chemical inhibitors and siRNA revealed that the protein kinase D (PRKD) family, mainly PRKD2, mediated BAZF gene expression by VEGF-A stimulation. A luciferase reporter assay showed that the promoter activity of the BAZF gene was unchanged by VEGF-A stimulation. However, we found that the stability of BAZF mRNA increased in a VEGF-A/PRKD2-dependent manner. In further studies to investigate the underlying mechanism, we successfully identified heat shock protein 90 beta (HSP90β) as a molecule that interacts with and stabilizes BAZF mRNA following VEGF-A/PRKD2 activation. These data suggest that HSP90β may positively regulate angiogenesis, not only as a protein chaperone, but also as an mRNA stabilizer for pro-angiogenic genes, such as BAZF , in a PRKD2 activity-dependent manner.